Heavy machine gun with a rotary barrel system, powered by a motor, usually electric, sometimes diesel. A motorized version of the gatling gun, which is technically a repeater rifle, since the action of operating the crank on the Gatling was required for each shot. Modern miniguns have rates of fire exceeding 166 rounds per second.

The US Navy employs miniguns in tandem with radar as an anti-missile system called Close-In Weapon System (CIWS).

The cannon on most modern jet fighters is usually a 20mm minigun, with the exception of the A-10 Warthog, which has a 30mm minigun.

Miniguns are seldom used by military infantry forces due to their propensity to devour ammunition, as it can easily go through more ammunition than an entire squad can carry in a few minutes or less.

(n) Any of the variants of General Electric's 20mm M61A1 Vulcan Gatling anti-materiel cannon system chambered for 7.62 NATO or smaller cartridges. The M134A1 minigun is an air-cooled, belt-fed machinegun utilizing a rotary assembly of (usually six) barrels to propel 7.62x51mm bullets at extremely high cyclic rates of fire, ranging from 600 to 6000 rounds per minute, depending on adjustments made to its electrical feed system. Logistically, the minigun is often used as a helicopter-mounted weapon, manned by a single gunner. An experimental version, the XM214, is another type of minigun chambered for the smaller 5.56 NATO cartridge.

The soldiers, with the help of their minigun-equipped helicopter, were able to make short work of the enemy and report back to base in time for chow.